So, how can we write a smart contract for trading tokens?

Now that we have learnt the basics of Solidity, we can write many

smart contracts and deploy them on the public Ethereum network as

per the business need. However, with the rising popularity of Solidity,

and many contracts deployed in production, the programmers

realized certain loopholes, and as a result, certain best practices

were created and followed as a standard.

2.5.25.1 Ethereum Request for Comments

An ‘Ethereum Request for Comments’ (ERC) is a document that the

smart contract programmers follow for using the Ethereum

blockchain platform. They describe the rules in these documents that

the Ethereum-based tokens must comply with.

2.5.25.2 ERC20

ERC20 is the most popular token standard and many tokens created

using the ERC20 standards are running on the Ethereum platform

today. ERC20 is fungible in nature, i.e., Fungibility is the ability of a

good or an asset to be interchanged with the other individual goods

or assets of the same type. The Fungible tokens are like digital cash

and are widely used in creating crypto currencies. Hence, if you wish

to create an ERC20 fungible token, you have to follow the standard

by implementing the following functions and events:

// SPDX-License-Identifier: SOME IDENTIFIER

pragma solidity ^0.8.10;

interface IERC20 {

function totalSupply() external view returns (uint256);

function balanceOf(address account) external view returns

(uint256);

function transfer(address recipient, uint256 amount)

external returns (bool);

function allowance(address owner, address spender) external

view returns (uint256);